In order to convert a DC voltage from a fuel cell or an electrochemical storage device into an AC voltage, in particular for feeding into a power grid, inverters are used, typically with a galvanic isolation being required between the input and the output.
Such inverters need to be designed for operation within a wide input voltage range, in particular in an input voltage range of from 1:2 to 1:3, since the DC voltage generated by a fuel cell, for example, can vary considerably, for example between 25 V and 72 V. In addition, it is possibly also necessary, for example for fuel cells, to supply the fuel cells with energy, for example for starting the operation of the fuel cell, for which purpose a DC voltage of 24 V, for example, needs to be supplied.
For generating an AC voltage of 230 V, for example, according to the prior art a three-stage design of the inverter with, for example, a step-down converter, an RF converter stage connected downstream thereof and the actual DC-to-AC converter, or with an RF converter stage, a step-up converter connected downstream thereof and the actual DC-to-AC converter.